SAN DIEGO
— Abe Shragge, curator of San Diego's Veterans Museum & Memorial Center, stumbled across a tiny Spanish-American War medal while searching through boxes of uncatalogued items. Barely the size of a thumb, the medal links a miniature cloth American flag to bronze emblems of an eagle, a crossed rifle and sword, and a seal.

In a museum with a bigger budget, the medal might be proudly displayed in a sealed protective case in a climate-controlled room. But here, the already tarnished medal will be exposed to damaging light and humidity in the expansive former military chapel that houses the museum.

In fact, nearly everything is vulnerable to San Diego's moist seaside climate, from military uniforms to flags to old paper documents. There's no air conditioning, so the doors are usually flung open, letting in plenty of outside air and sunlight.

Mr. Shragge knows this isn't good for the museum's treasured collection of military memorabilia dating to the Civil War. But, he says, the reality is that "we have limited staff, funding, and expertise to do all the things we need to do."

In a recent report, the most extensive of its kind, a watchdog group warns that thousands of American museums are in similar straits. A survey of 3,370 institutions by the nonprofit group Heritage Preservation found that some 612 million artifacts - from photographs and paintings to nature specimens and pottery - are at risk of deterioration because they aren't cared for properly.

Nearly 60 percent of institutions surveyed acknowledged that light has damaged their collections, while 53 percent said moisture caused problems. And, like the Veterans Museum in San Diego, 26 percent of those surveyed have no special controls in place to protect their collections from light, temperature, and humidity.

The report, issued in December, lists several stories of museum preservation gone wrong. A lack of proper climate control at the American Museum of Natural History in New York City, for example, has damaged the hides of its preserved elephants. Insect infestations and a steam leak threaten to destroy the University of Connecticut's huge collection of preserved animal life. In Washington, D.C., improper climate control at the city's public-records office threatens the last will and testament of black abolitionist leader Frederick Douglass.

Back in San Diego, Shragge says he knows his museum needs to better preserve its collections, and he's been working to buy protective containers. Volunteers are helping to scan photos and documents so they'll be preserved even if they fall apart.

But not every improvement is on tap. Climate control? "That's something I dream about," Shragge says. After all, the museum's annual budget is only about $200,000, and funds are hard to come by.

"My sense is that it's getting more and more difficult to generate donations and grants," Shragge says. "I don't know how we'd do it without someone who's really skilled in raising money and going after the larger kinds of grants that can really support an institution like this."

To make matters more difficult, the museum is little-known, even though it's in San Diego's landmark Balboa Park, home to the San Diego Zoo and one of the largest groupings of museums in the US.

Besides relying on small budgets and volunteers who may not have specialized knowledge about collection preservation, many museums also face equipment problems. "It's a real challenge to get funding for unsexy things," says Cindy Stankowski, director of the San Diego Archaeological Center, which collects and stores artifacts dug up during local construction. "When the HVAC [climate-control system] goes down or you need shelving, people are saying, 'Shelving? Who cares?' "

What is a struggling museum to do? Museum advocates say one answer to the funding dilemma lies in the collections themselves, especially those kept behind closed doors. Contrary to what some curators believe, patrons are fascinated by opportunities to poke around behind the scenes and learn about less-publicized efforts, advocates say. And cash can come with the appreciation. "If people know what's behind the scenes, what a museum or library has, they'll be more appreciative of the need to take care of the cost of doing that," says Larry Reger, president of Heritage Preservation in Washington, D.C.

Some museums let ordinary patrons observe day-to-day preservation efforts as well as regular displays, while others offer special tours. The San Diego Natural History Museum, which spotlights nature in Southern California and Baja California, has embraced both approaches.

Over the past 15 years, the museum has found funds to preserve its 8.5 million specimens by making the public and the research community aware of its presence, says executive director Michael Hager. Tour groups regularly walk through the museum's backrooms, watching workers clean fossils and catalog animal species. A museum remodel will allow visitors to watch conservators on the job. And on another front, the museum regularly enlists volunteers to help gather samples. Currently, 320 local "parabotanists" are canvassing the estimated 2,310 plant species that grow naturally in San Diego County for a botanical atlas that will be published later this decade. The volunteer efforts will add to that number and allow the museum to map where the species grow.

Without public outreach efforts, people become "disconnected" from science and fail to realize the work that's being done, says botany curator Jon Rebman.

There's an even bigger risk to keeping collections under wraps, says museum director Mr. Hager, who spearheaded efforts to build a new $38 million extension in 2001. "If the collections are unused," he says, "there's a lot of people who wonder why you have them in the first place." And apathy is the first step toward deterioration.

Hurricane Katrina was a wake-up call for museum collections

The staff at Ohr-O'Keefe Museum of Art knows the drill. Days before hurricane Katrina landed on the Gulf Coast, employees of the Biloxi, Miss., museum began packing pottery into boxes bound for the second floor and scouring the historic house of a former slave for artifacts that needed higher ground.

"We put the whole plan into place that we'd been practicing for many years," says executive director Marjie Gowdy.

Their efforts worked. The hurricane destroyed the old house and damaged some buildings, but the one that housed the pottery and artifacts held up.

Other museums and historic sites in Biloxi weren't so fortunate. Floodwaters destroyed exhibits and collections at several institutions, including the Beauvoir estate of Confederate President, Jefferson Davis.

"This little strip of land along the Gulf Coast is so rich culturally and historically, and now a huge amount is lost forever," Ms. Gowdy says.

Much of the damage was unavoidable. But some artifacts could have been saved if more institutions had been better prepared for a disaster.

Emergency plans are in place at only 20 percent of the nation's collecting institutions, according to Heritage Preservation in Washington, D.C. The conservation group is calling attention to the lack of preparedness and the risks presented by disasters ranging from tornadoes to broken water pipes. In the wake of Katrina, "there's lots of discussions going on and a lot of lessons that have been learned," says Larry Reger, the organization's president.